diff options
Diffstat (limited to 'pgm1')
| -rw-r--r-- | pgm1/beetle.c | 140 | ||||
| -rwxr-xr-x | pgm1/makefile | 36 |
2 files changed, 176 insertions, 0 deletions
diff --git a/pgm1/beetle.c b/pgm1/beetle.c new file mode 100644 index 0000000..6b8a971 --- /dev/null +++ b/pgm1/beetle.c @@ -0,0 +1,140 @@ +#include<stdlib.h> +#include<stdio.h> +#include<math.h> +#include<errno.h> + +/* + * The purpose of this program is to simulate and record the average lifetimes + * of beetles on cardboard squares, suspended over vats of boiling oil. It takes + * in two parameters, both positive, long integers. The first integer refers + * to the length of one side of the cardboard square, in inches. The second + * refers to the number of beetles (number of times) with which to run this + * simulation. + * + * usage: ./beetle int int (./beetle square_size number_of_beetles) + */ + +long double simulateLifetime(long int squareSize, long int beetleCount) { + /* + * simulateLifetime returns the collective lifetime of the beetles + * suspended over the vat of oil. If this function fails to simulate any + * beetles, it will return -1. + * + * This simulation places a beetle at the center of a cardboard square. + * The cardboard square is represented by a coordinate grid, with the origin + * being at the top-left corner, or the "home position". The + * beetle picks a random angle to move in, represented by random(),and moves + * forward 1 inch. This movement takes 1 second. The beetle waits 1 more + * second before starting the whole process over again. Once the beetle's + * coordinates move off the bounds of the coordinate grid, it "falls into + * the vat" and the simulation continues with the next beetle, decreasing + * the count. + * + * long int squareSize - represents the size of one side of the cardboard + * square. + * + * long int beetleCount - represents the number of beetles to simulate, or + * rather, the number of times to run the simulation. + */ + + long double beetleX; + long double beetleY; + long double lifetime; + double angle; + long int count; + long int seconds; + + lifetime = -1; + count = beetleCount; + seconds = 0; + + while (count > 0) { + beetleX = squareSize / 2; + beetleY = squareSize / 2; + seconds = 0; + + while (beetleX >= 0 && beetleY >= 0 && beetleX <= squareSize + && beetleY <= squareSize) { + angle = random(); + beetleX += cos(angle); + beetleY += sin(angle); + seconds++; + + if (beetleX >= 0 && beetleY >= 0 && beetleX <= squareSize + && beetleY <= squareSize) { + seconds++; // the beetle is resting but hasn't fallen off edge + } + } + + lifetime += seconds; + count--; + } + + return lifetime; +} + +int main(int argc, char *argv[]) { + /* + * main sets up the beetle program. It reads the user's input and checks it + * to make sure that it is valid. It converts the input to values that the + * simulation function can use and then calls simulateLifetime(). main then + * prints the output to the console. + */ + long double lifetime; + long int squareSize; + long int beetleCount; + char *squareTest; + char *countTest; + + // Check for improper number of arguments + if (argc != 3) { + fprintf(stderr, "beetle: usage: ./beetle int int\n"); + exit(1); + } + + errno = 0; // Reset error status + squareSize = strtol(argv[1], &squareTest, 10); + beetleCount = strtol(argv[2], &countTest, 10); + + // Check for invalid input + if (squareTest == argv[1] || countTest == argv[2]) { + fprintf(stderr, "beetle: usage: ./beetle int int\n"); + exit(1); + } + + // Check for negative input + if (squareSize < 0 || beetleCount < 0) { + fprintf(stderr, "beetle: error: input must be positive integers\n"); + exit(1); + } + + // Check for overflow/underflow + if (errno == ERANGE) { + fprintf(stderr, "beetle: error: int too large\n"); + exit(1); + } + + // If no square to use for simulation then finish + if (squareSize == 0) { + fprintf(stderr, "No square given so lifetime is 0\n"); + exit(0); + } + + // If no beetles given then finish + if (beetleCount == 0) { + fprintf(stderr, "No beetles given, so lifetime is 0\n"); + exit(0); + } + + // Run simulation and check return value + if ((lifetime = simulateLifetime(squareSize, beetleCount)) == -1) { + fprintf(stderr, "beetle: error: beetles have achieved immortality!\n"); + exit(1); + } + + // Take the average of the beetles' lifetime and print the output. + lifetime = lifetime / beetleCount; + printf("%li by %li square, %li beetles, mean beetle lifetime is %.1Lf\n", + squareSize, squareSize, beetleCount, lifetime); + exit(0); +} diff --git a/pgm1/makefile b/pgm1/makefile new file mode 100755 index 0000000..7be689d --- /dev/null +++ b/pgm1/makefile @@ -0,0 +1,36 @@ +all: beetle + +beetle: beetle.c + gcc -Wall -o beetle beetle.c -lm + +debug: beetle.c + gcc -Wall -o -g beetle beetle.c -lm + +clean: + rm -f beetle + +test: + gcc -Wall -o beetle beetle.c -lm + + # standard test case + ./beetle 10 10000 + + # too many/too few inputs + -./beetle 10 + -./beetle 10 10 10 + + # negatives + -./beetle -10 10000 + -./beetle 10 -10000 + + # non-number characters + -./beetle abc 10000 + -./beetle 10 abc + + # really big numbers + -./beetle 2147483647 2 + -./beetle 2 2147483647 + + # overflow + -./beetle 10 100000000000000000000000000000 + -./beetle 100000000000000000000000000000 2 |